Though vaccine won’t protect against all strains, it still can help

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With the winter weather moving in and cold season upon us, many people are rushing to get their flu vaccine before they need to use a single sick day.

However, this season’s flu vaccine may not be as foolproof in heading off the virus. U.S. health officials said this week the current vaccine does not protect well against the dominant strain seen most commonly so far this year. That strain tends to cause more deaths and hospitalizations, especially in the elderly.

“Antibodies made in response to vaccination with one flu virus can sometimes provide protection against different but related viruses,” Bozarth said. “So, a less than ideal match, as we appear to be seeing this season, can still provide some protection against the influenza illness.”

For the past several years, the number of people getting an annual flu shot has risen. According to the CDCs website, the number of adults getting the vaccine has risen a bit while the number of children receiving the vaccine has gone up 2.3 percent.

Currently there are several types of trivalent, or three component, vaccines to treat the different strains of flu: intramuscular, intradermal and nasal spray vaccines. For the current season, experts recommend children 2 to 8 get the spray vaccines after recent studies suggest it may work better than a traditional flu shot.

“The flu vaccine contains three or four flu viruses, depending on the type of vaccine you receive, so even when there is low effectiveness for one virus, the vaccine may protect against the other viruses,” said Bozarth. “Even during seasons when there is a less than ideal match, the CDC recommends the flu vaccine for everyone 6 months and older.”

In addition to getting a vaccine, there are other steps you can take to prevent the spread of the flu:

Be sure to clean and disinfect surfaces that may be contaminated by the flu virus.

Try to avoid touching your eyes, nose and mouth, especially when around others.

If you do begin to show flu symptoms ­­— fever, cough, sore throat, runny or stuffy nose, body aches, headaches, chills and fatigue — be sure to stay home at least 24 hours after your fever is gone.

Flu vaccine effectiveness tends to vary from year to year. Last winter, flu vaccine was 50 to 55 percent effective overall, which experts consider relatively good.

Nearly 150 million doses of flu vaccine have been distributed for this winter’s flu season.

“Though we cannot predict what will happen the rest of this flu season, it’s possible we may have a season that’s more severe than most,” said Dr. Tom Frieden, director of the Centers for Disease Control and Prevention, at a news conference Thursday.

Current flu vaccines are built to protect against three or four different kinds of flu virus, depending on the product. The ingredients are selected very early in the year, based on predictions of what strains will circulate the following winter.

The ingredients always include a Type A H3N2 flu virus. The most severe flu seasons tend to be dominated by some version of that kind of flu bug. The three most deadly flu seasons of the last 10 years — in the winters of 2003-2004, 2007-2008, and 2012-2013 — were H3N2 seasons.

In March, after the H3N2 vaccine strain was vaccine production was underway, health officials noted the appearance new and different strain of H3N2.

“This is not something that’s been around before,” Frieden said.

But health officials weren’t sure if the new strain would become a significant problem in the United States this winter until recently, they said. Lab specimens from patients have shown that the most commonly seen flu bug so far is the new strain of H3N2. Specifically, about 48 percent of the H3N2 samples seen so far were well matched to what’s in the vaccine, but 52 percent were not, the CDC said.

An official with one vaccine manufacturer — GlaxoSmithKline — emphasized that about half the samples do match the strain in the vaccine. He also noted flu seasons can sometimes involve a second wave of illnesses caused by a different strain.

“We’re at the very beginning of flu season, and it’s quite possible different strains will predominate,” said Dr. Leonard Friedland, director of scientific affairs for GSK’s vaccines business.